1. Field of the Invention
This invention relates to an adjustable shelf assembly and more particularly to an assembly in which a shelf support is vertically and angularly adjustable by means of T-shaped projections at the base of the support which engage corresponding T-shaped openings in a vertical channel.
2. Description of the Prior Art
Due to a wide variety of uses for shelving, many ways have been suggested to provide an adjustable shelf assembly. The desirability of a shelf support which is vertically adjustable alone is evidenced by numerous patents. In addition, the desirability of a support which is also angularly adjustable has been clearly indicated, exemplary assemblies are disclosed by U.S. Pat. No. 3,089,675 to Lozier, U.S. Pat. No. 3,093,094 to Oztekin and U.S. Pat. No. 3,182,945 to Sedo.
For the most part, assemblies of the prior art utilize lightweight sheet metal shelf supports that have flat and notched or stepped projections at the base of the support for varying the relative angle of the shelf. These projections typically engage corresponding rectangular slots or openings in a vertical channel which has a series of these slots to provide for vertical adjustment. Assemblies which depend on projections and slots of the type mentioned fail to provide suitable rigidity or stability against the jars and vibration typically occuring on a shelf. In addition, when the overlying shelf is subject to a heavy load, the thin, flat projections do not offer sufficient resistance to the shear forces produced.
Thus, it has been determined that a shelf support having a T-shaped projection is desirable in many applications. Assemblies incorporating this feature have been taught in U.S. Pat. No. 3,080,980 to Gibbons and U.S. Pat. No. 4,156,515 to Mochly. However, neither of these references couples a T-shaped projection with the capability for angular adjustment. Although U.S. Pat. No. 3,085,693 to Shell illustrates the use of a separate T-shaped extension to allow the shelf support to slope downwardly, a separate element interjects instability into the assembly even though the T-shape would provide greater strength. In these assemblies which use the T-shape projections, the vertical channels utilize conventional rectangular slots or openings which do not facilitate use of a T-shaped projection, since the support must be rotated or manipulated in some way before it can be located in the column.